Kundt's Tube

This video is taken from the demo lab of NUS High School. The student there made this Kundt's tube.

Kundt's tube is an experimental acoustical apparatus invented in 1866 by German physicist August Kundt.

That time, it was used to measure speed of sound in gas or solid rod.

Today, we used it to demonstrate standing waves and acoustical force.

To make this tube, we need a transparent horizontal pipe with styrofoam beads inside. Do note, do not use styrofoam beads that are too small as static will cause them to stick to the wall of the tube. I saw online that some put cork duct or talc in it, but I never tried before so not sure whether it works.

Then block one end and attached another end to a loud speaker that is attached to a signal generator to produce a sine wave.

Then you will see like what is appearing in this video.

DIY cloud chamber

Cloud chamber is a device that can be used to detect/show cosmic rays (particles from the universe). Cosmic rays are harmless and are invisible to us. Presence of cosmic ray will show a trace/track that run across inside the cloud chamber.

I get to learn how to make a cloud chamber from NUS High School of Math & Science. The video here show our DIY cloud chamber and the trace of cosmic ray. In the DIY cloud chamber, the trace cause by the ray look like shooting stars.

While in a real cloud chamber, the trace look like fire works. Partly because we purposely put an radioactive material in the middle to create the cosmic ray so we do not need to wait too long to see its trace. Here's the video of the real cloud chamber.

Here's the brief instruction on how to make your own cloud chamber. Making it is easy however you may need to buy absolute isopropyl alcohol (pure / >99%) which may not be available commercially. You need to get it from those chemical supplier.

*Do note this isopropyl alcohol is denatured type, so do not drink it if you have excess of it from the experiment.

Things you need:

1) A clear plastic container (we use those tea bag container (w lid) from Ikea, but we don't need the lid)

2) Wooden Tray / shallow styrofoam box that is bigger than the clear plastic container.

3) A big piece of felt / absorbing cloth (available from Daiso)

4) Aluminium plate with black epoxy coating slightly bigger than the clear container but still able to fit into the wooden / styrofoam box.
*Paint coating aluminium is not suitable as it will peel off when contact with dry ice for too long.

5) Strip of LED light (length = perimeter of the clear container)

Procedure:

1) Roll up the felt and stick around the bottom of the clear container. We drill hole onto the container so string can go through and tied the felt to the container. As the felt must be able to stick there and not dropped when wetted with isopropyl alcohol.

2) Cut a rectangular felt where the perimeter is the same as the clear container (to seal the gap between the container and the aluminium plate)

3) Put dry ice in the wooden / styrofoam box.

4) Put the black aluminium plate on top of it.

5) Wet the rectangular felt and the felt inside the container with isopropyl alcohol. Do not add too much till the alcohol is dripping.

6) Invert it and put on top of the black aluminium plate

7) Put the LED light around it.

The coldness from the dry ice will cause the vapour to condense to form small droplets. When the ray pass by, these droplets will form track which you have seen it in the video.

My own video production on lab safety

Hi all, it has been quite some time that I did not write my blog. Partly is I am too busy & also I have nothing interesting to share.

As I have to do lab safety briefing for students at the start of the year. Using power slides to show all the lab safety rules will bored the students in this era where everything is shown with pictures & videos.

So I have decided to make a video from the 30 lab safety rules together with my school Media Studies student. I am quite impress with the students that are in the video. They can act and even do filming themselves. All the shots were created by the students themselves. I only told them what I want to show, then they know which angle or position they need to stand or film in order to get a good shot.

So instead of keeping such a good educational video only to ourselves. I would like to share this information to everyone and educate them on the importance of lab safety.

Here the link to the video. Hope you will like it.

Eating liquid nitrogen biscuit

Have you tried eating a biscuit that has been dipped into the liquid nitrogen? What will happen? Don't worry it will not be very cold to cause frost bite in your mouth. As you are eating the biscuit not drinking liquid nitrogen. (Please do not drink liquid nitrogen as it will kill yourself!). The taste of it? No taste of the biscuit only feel cold and dry.

The moment you eat it, the heat from your body will cause the liquid nitrogen to become gas. Hence what will happen? You will look like an angry bull with smoke coming out from your mouth & nose. Here is the video, happy viewing!

YBCO floating on neodynium magnet

Hi all, here is an interesting experiment. When you cool a YBCO (a kind of superconductor) using liquid nitrogen and placed it on top of the neodynium magnet, it will create a meissner effect which will allows the YBCO to float on top of the neodynium magnet as shown in the video.

Do note, it need strong magnetic field, in order to let it float. So neodynium magnet is needed and not other normal magnet. The theory behind it that cause the floating is quite complicated so I will not touch on that. I only want to show the video, how amazing it is to see something floating.

Blood grouping with artificial blood

I tried to search online for the recipe. Actually I did saw different recipe and tried it out, but because online did not mentioned on the concentration used and the brand of the dye. My experiment fails with their recipe.

I did get agglutination when I react HCl with silver nitrate (recipe from online). However the agglutination is white colour in a pool of red water.

If you all seen a real blood grouping before using blood and the serum with different antibodies, the agglutination is actually red in a pool of pale yellow solution (which is serum). Below are my recipe:

Blood Gp A - Star brand Red Dye + Tap water

Blood Gp B - 10% FeCl3 (Iron III Chloride) + Char Siew powder (to give red colour)

Blood Gp O - Char Siew powder + Tap Water

* Star brand Green dye is used to adjust the red colour to look more like blood.

Anti A - 0.1M HCl (Hydrochloric Acid)

Anti B - 0.1M NaOH (Aq Sodium Hydroxide) 

So after a few trial with different chemical, I finally come out with my own recipe. All thanks to Star brand red dye which agglutinate in the presence of acid.

However I do have a problem is that I cannot make Blood AB as the Red dye (from Blood A) will agglutinate in the presence of FeCl3 which is acidic even no acid is added (I only mixed 5g of FeCl3 powder with 50ml of tap water and it gives a pH of about 1.5)

So I intend to leave out Blood AB, as after a lot of trial, I still cannot get the result I want. I even let the agglutination in my Blood AB to settle down and get the supernatant. However it only react with Anti B (NaOH) but not in Anti A (HCl) which I think all have been reacted to form agglutination so the supernatant does not gives a reaction when react with Anti A (HCl).

If anyone who read my article can create Blood AB, or you have any recipe where the result is as good as mine shown in the picture (really look like real life blood agglutination). Please leave comment in my blog. Thank you.

Attached below is the picture of the item I used for my blood grouping kit.